Their margins are very low indeed. This has advantages of course (low cost provider) but it also means they are quite tiny compared to the big beasts (Intel, Apple etc.) I have argued that ARM should move into making their own solutions and move up the value chain, but that's a different business model altogether.

@kiran
Intel's presence in the list may be discredited (see earlier comments in this forum).
TSMC is involved because it makes the chips for many ARM licensees ..and is therefore intimately involved in being licensed itself to integrate ARM cores using ARM physical IP, holding ARM cores and physical IP in its libraries.
Both the foundry and the fabless are held accountable by ARM although the balance of payments depends on the nature and the detail of the licenses.

Not sure how useful this retrospective is, since ARM is just a few weeks away from announcing 2011 (and 4Q11) numbers. However as Peter notes, since this is revenue, you have to look at units multiplied by per chip royalty (which is a % of ASP). More public info - we shared that for 4Q10 (which is based on actual shipments from our silicon partners during 3Q10) that Cortex (A, R and M) was 13% of the 1.8BU shipments for that quarter. We also showed publically that Cortex-A shipments for that quarter was ~55M. So that leaves 234-55 =179M split between Cortex-R and M. MCU shipments for 2010 (which includes some legacy ARM7 and ARM9 devices) was pretty significant overall. But the significantly higher ASPs of apps processors wins out.

Apart from being of questionable provenece, this list is from 2010, which was that bit earlier in the rise of ARM microcontrollers.
The main thing would be that microcontrollers sell for much lower ASPs than microprocessors but the royalty rate tends to be the same percentage rate. So NXP would have to sell a a lot of MCUs to start to climb up any ranking. But perhaps they did in 2011?